Glossary of terms related to antifungal stewardship

We’ve prepared a Glossary of terms related to anti fungal stewardship.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

A

Acute Myeloid Leukaemia (AML)

A cancer of the white blood cells and bone marrow.

Antibiogram

The result of laboratory testing for the sensitivity of an isolated bacterial strain to different antibiotics. Antibiograms can be collated to form cumulative antibiograms, which can help to form prescribing guidelines at a hospital, regional or national level.

Antifungal

A drug that selectively eliminates fungal pathogens from a host with minimal toxicity to the host.

Antifungal Susceptibility Testing (AST)

A generic term for the laboratory measurement, achievable using different methods, of the levels of susceptibility or resistance shown by fungal isolates to antifungals. It may for example, involve disc diffusion testing or MIC determination.

Antimicrobial

A chemical substance that kills or inhibits the growth of microorganisms such as bacteria, viruses or fungi. (See also: antifungal, which is a class of antimicrobial).

Antimicrobial Stewardship

An organisational or healthcare-system-wide approach to promoting and monitoring judicious use of antimicrobials to preserve their future effectiveness

Aspergillus

Aspergillus is a common type of fungus (mould). It can be found in many places including heating or air conditioning systems and rotting material such as hay or compost. Its spores are present in the air we breathe but does not normally cause illness. In those people with a weakened immune system, damaged lungs or with allergies, Aspergillus can cause disease.

Aspergillosis

A common condition caused by aspergillus mould. There are several different types of aspergillosis, most affect the lungs and cause breathing difficulties.

Azoles

Fluconazole, itraconazole, and ketoconazole inhibit cytochrome P450-dependent enzymes involved in the biosynthesis of ergosterol, which is required for fungal cell membrane structure and function.

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B

β-1-3-D-glucan

A component of the cell wall of many fungi.

Basophil

A type of white blood cell.

Biofilms

An assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix.

Biomarker

Tests that can be used to follow body processes and diseases in humans and animals. They can be used to predict how a patient will respond to a medicine or whether they have, or are likely to develop, a certain disease.

Blood Culture

A microbiological culture of blood, which usually is a sterile environment. It is employed to detect infections that are spreading through the bloodstream, mainly in patients with sepsis.

Bronchoalveolar lavage (BAL)

A medical procedure in which a bronchoscope is passed through the mouth or nose into the lungs and fluid is squirted into a small part of the lung and then collected for examination.

Bronchoscopy

A bronchoscopy is an examination of the breathing passages (airways) of a patients lungs. The bronchoscopy is carried out with a thin tube-like instrument with a mini camera at its tip, called a bronchoscope, usually while the patient has received sedation medicine.

Budding

A method of asexual reproduction, occurs in most yeasts and in some filamentous fungi. In this process, a bud develops on the surface of either the yeast cell or the hypha, with the cytoplasm of the bud being continuous with that of the parent cell. The nucleus of the parent cell then divides; one of the daughter nuclei migrates into the bud, and the other remains in the parent cell. The parent cell is capable of producing many buds over its surface by continuous synthesis of cytoplasm and repeated nuclear divisions. After a bud develops to a certain point and even before it is severed from the parent cell, it is itself capable of budding by the same process. In this way, a chain of cells may be produced. Eventually, the individual buds pinch off the parent cell and become individual yeast cells. Buds that are pinched off a hypha of a filamentous fungus behave as spores; that is, they germinate, each giving rise to a structure called a germ tube, which develops into a new hypha.

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C

Candida

Candida albicans is a type of yeast (fungus) that is a common infection in the mouth. Usually, it is not a serious infection. It likes to infect moist places such as the mouth (although it can also affect wounds and the genitals). The mouth infection is called oral candidiasis or oral candidosis (commonly known as oral thrush).

‘Candida Score’

Candida score is a diagnostic tool used in the ICU setting. Patients are swabbed for the presence of colonising Candida species in multiple sites. Such sites would be the groin, intravenous lines, endotracheal tubes, urine samples. The higher the number of colonised sites on an individual, the higher the score. High scores can then be used to select patients who are more likely to benefit from early, empirical antifungal treatment. It applies mainly to patients who are critically ill, whose clinical picture is suggestive of invasive fungal infection (candidaemia).

Candidemia

Infection of the bloodstream with fungi of the genus Candida (as C. ablicans or C. parapsilosis). It is the most common fungal bloodstream infection in hospitalized patients. Mortality is very high. It reaches 50% in some studies. Although Candida albicansis still the most common Candida species causing candidemia, in recent years there has been an increase in nonalbicans Candida species, which may represent a therapeutic challenge given the different antifungal susceptibility profile of different Candida species. This new trend is likely caused by the process of natural selection of resistant species to the most common antifungals used.

Central Nervous System (CNS)

Part of the nervous system which in vertebrates consists of the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, and which coordinates the activity of the entire nervous system.

Cerebrospinal Fluid (CSF)

A watery fluid that is continuously produced and absorbed and that flows in the ventricles within the brain and around the surface of the brain and spinal cord.

COPD

Chronic Obstructive Pulmonary Disease causes impairment of respiratory reserve and may be caused or worsened by smoking. It is considered to be a major risk factor in major surgery.

C-reactive Protein

A protein made by the liver thay is relased into the blood in response to inflammation.

Creatinine

A waste product from the normal breakdown of muscle tissue and used as a measure of kidney function in blood tests.

Cryptococcus

Cryptococcus is a type of fungus that is found in the soil worldwide, usually in association with bird droppings. The major species of Cryptococcus that causes illness in human is Cryptococcus neoformans. Another less common species that can also cause disease in humans is Cryptococcus gattii.

Cryptococcosis

Disease caused by C. neoformans & C. gattii that typically infects immunocompromised persons. C. neoformans is abundant in soil contaminated by pigeon droppings. C. gattii is normally found in the tropics and is associated with red gum trees.

CT Scan

A computerised tomography (CT) scan uses X-rays and a computer to create detailed images of the inside of the body. CT scans can produce detailed images of many structures inside the body, including the internal organs, blood vessels and bones. They can be used to diagnose conditions, guide further tests or treatments and monitor conditions.

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D

Debridement

The excision or wide removal of all dead (necrotic) and damaged tissue that may develop in a surgical wound.

Dermatophytes

Fungal organisms that require keratin for growth. These fungi can cause superficial infections of the hair, skin, and nails. Dermatophytes are spread by direct contact from other people, animals, soil, and from fomites.

Dimorphic Fungi

Fungi that have a yeast (or yeast-like) phase and a mould (filamentous) phase.

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E

Echinocandins

Echinocandins are potent inhibitors of fungal cell wall synthesis, by means of their effects on β-1,3-glucan synthase. These agents bind rapidly to the fungal enzyme, causing rapid cell death of the fungus.

Efficacy

The extent to which medical interventions achieve health improvements under ideal circumstances.

Embolization

A procedure in which the blood supply to a tumour or an abnormal area of tissue is blocked.

Eosinophil

A type of white blood cell.

Epidemiology

The study of factors that have an impact on disease in the human community. Often used in the control of health problems.

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F

Flucytosine

An antifungal agent that is used to treat fungal infections especially by members of the genera Candida and Cryptococcus (especially Cryptococcus neoformans).

Fungi

Non phototrophic eukaryotic microorganisms that contain rigid cell walls. Fungi are heterotrophs (cannot make their own food) and have important roles in nutrient cycling in an ecosystem. Fungi reproduce both sexually and asexually, and they also have symbiotic associations with plants and bacteria. However, they are also responsible for some diseases in plants and animals.

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G

GORD

Gastro-Oesophageal Reflux Disease. is a common condition, where acid from the stomach leaks up into the oesophagus (gullet). It usually occurs as a result of the ring of muscle at the bottom of the oesophagus becoming weakened. GORD causes symptoms such as heartburn and an unpleasant taste in the back of the mouth. It may just be an occasional nuisance for some people, but for others it can be a severe, lifelong problem.

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H

Haematocrit

The ratio of the volume of red blood cells to the total volume of blood.

Haemoglobin

A protein found in the red blood cells that carries oxygen in your body and gives blood its red colour.

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I

Infection

The invasion and reproduction of pathogenic (disease causing) organisms inside the body. This can cause tissue injury and progress to disease.

Infectivity

The measure of the ability of a pathogen to cause infection.

Infection Control

Infection control prevents or stops the spread of infections in healthcare settings.

Inflammatory Response

The body’s reaction to many infections, mediated by the immune system.

Invasive Aspergillosis

A serious infection that usually affects people who have weakened immune systems, such as people who have had an organ transplant or a stem cell transplant. Invasive aspergillosis most commonly affects the lungs, but it can also spread to other parts of the body. See Aspergillosis.

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J

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K

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L

Lymphocyte

A type of white blood cell.

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M

Magnetic Resonance Assay

Qualitative molecular diagnostic method that can detect and speciate the 5 most common Candida spp.; namely, Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Candida krusei, in approximately 5 h.

Mean Corpuscular Volume (MCV)

A measurement of the average size of red blood cells.

Microscopy

Use of a microscope.

MIC (Minimum Inhibitory Concentration)

The Minimum Inhibitory Concentration (MIC) is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism. MICs are used by diagnostic laboratories mainly to confirm resistance, but also as a research tool to determine the in vitro activity of new antimicrobials.

Monocyte

A type of white blood cell.

Moulds

Filamentous fungi.

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N

Neutropenia

Neutropenia is a condition in which the number of neutrophils (a type of white blood cell) in the bloodstream is decreased, affecting the body’s ability to fight off infections. Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1500 per microliter (1500/microL); severe neutropenia is defined as an ANC of less than 500/microL.

Neutrophil

A type of white blood cell.

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O

Oedema

Swelling due to the accumulation of interstitial tissue fluid and frequently a result of bacterial infection in a wound.

Opportunistic Pathogens

An infectious microorganism that is normally a commensal or does not harm its host but can cause disease when the host’s resistance is low, for example due to a weakened immune system.

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P

Pathogen

A disease causing microorganism.

Pathogenicity

The ability of a pathogen to cause disease.

PCR

Stands for Polymerase-chain reaction. It is a technology in molecular biology used to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. It is used in Microbiology to identify the presence of bacterial, fungal or viral DNA or RNA in clinical samples.

Platelets

Components of blood whose function is to prevent bleeding from blood vessel injury by clumping and forming a blood clot.

Pneumocystic jiroveci pneumonia (PCP)

A serious infection caused by Pneumocystis jirovecii that causes inflammation and fluid build-up in the lungs.

Polyenes

An antifungal agent which works by interacting with sterols in the cell membrane to form channels through which small molecules leak from the inside of the fungal cell to the outside. Amphotericin, nystatin, and pimaricin are examples of polyenes.

Post-mortem

An examination of a dead body to determine the cause of death.

Pulmonary Infection

An infection of the lungs or large airways.

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Q

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R

Resistance

A property of some microbes which renders certain antimicrobials ineffective against them in the laboratory or when they are used to treat infections. Resistance may be an intrinsic characteristic or may be acquired and selected by exposure to antimicrobials. The latter category frequently has greater public health significance.

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S

Serology

The scientific study or diagnostic examination of blood serum, especially with regard to the response of the immune system to pathogens or introduced substances.

Spores

A general term used for resistant resting structures formed by many prokaryotes and fungi.

Strain

A population of cells of a single species all descended from a single cell: a clone

Superficial

On the surface or shallow. Skin infections are described as superficial infections.

Surveillance

Surveillance of antimicrobial resistance is the tracking of changes in microbial populations.

Systemic Infections

An infection which has spread to multiple parts of the body.

Systematic Review

A review in which evidence from scientific studies has been identified, appraised and synthesised in a methodical way according to predetermined criteria. The review may include a meta-analysis.

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T

Terbinafine

An antifungal agent

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U

Ultrasound

A procedure that uses high frequency sound waves to create an image of part of the inside of the body, such as the heart. Ultrasound Scans can be used: to help doctors make a diagnosis or to assess the effects of a treatment, to study blood flow and to detect any narrowing or blocking of blood vessels; or during a Maternity Episode to produce images of the baby in the womb.

Urea

The main waste product of protein metabolism in humans. Blood tests use urea concentration as a measure of kidney function.

UTI

Urinary Tract Infection, common infections that can affect the bladder, the kidneys and the tubes connected to them. Anyone can get them, but they’re particularly common in women. Some women experience them regularly (called recurrent UTIs). UTIs can be painful and uncomfortable, but usually pass within a few days and can be easily treated with antibiotics.

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V

Virulence

The relative ability of a pathogen to cause disease.

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W

White Cell Count (WCC)

A test that measures the number of white blood cells in the blood.

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X

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Y

Yeast

A microscopic fungus consisting of single oval cells that reproduce by budding, and capable of converting sugar into alcohol and carbon dioxide, e.g. Candida

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Z

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